1. Field of the Invention
The present invention relates to an electro-luminescence display panel, and more particularly to a simplified structure and process of making a thin film transistor array of an EL display panel.
2. Description of the Related Art
Various flat panel display devices have been developed which overcome the weight and size disadvantages of a cathode ray tube (CRT) display device. These flat panel display devices include liquid crystal display (LCD) devices, field emission display (FED) devices, plasma display panel (PDP) devices, and electro-luminescence (EL) display panel devices.
The EL display panel is a self luminous device which makes phosphorus emit light by re-combining electrons and holes. An EL display panel is broadly classified as an inorganic EL or an organic EL based on the material employed in the panel. The EL display panel has many advantages such as low drive voltage, self-luminescence, thin film type, wide viewing angle, fast response speed, high contrast and so on. As a result it is considered to be a next generation display device.
An organic EL device includes an electron injection layer, an electron transport layer, a light-emitting layer, a hole transport layer, and a hole injection layer which are generally deposited between an anode and a cathode. When a designated voltage is applied between the anode and the cathode of an organic EL device, the electrons generated from the cathode move to the light-emitting layer through the electron injection layer and the electron transport layer, and the holes generated from the anode move to the light-emitting layer through the hole injection layer and the hole transport layer. Accordingly, the electrons and the holes supplied from the electron transport layer and the hole transport layer are recombined to emit light in the light emitting layer.
FIG. 1 illustrates an active matrix organic EL display panel. As illustrated in FIG. 1, the organic EL device includes a pixel matrix 20 having a plurality of pixels 28 arranged in areas defined by the crossing of a gate line GL and a data line DL; a gate driver 22 driving the gate lines GL of the pixel matrix 20; and a data driver 24 driving the data lines DL of the pixel matrix 20.
The gate driver 22 sequentially drives the gate lines G1 by supplying a scan pulse. The data driver 24 supplies a data signal to the data lines whenever the scan pulse is supplied. Each pixel 28 receives a data signal from the data line DL to generate light corresponding to the data signal when the scan pulse is supplied to the gate line GL.
In the related art organic EL display panel, a thin film transistor substrate is formed by a plurality of mask processes inclusive of a semiconductor process, thus there is a problem in that its manufacturing process is complicated.